In reference to your question, in the unlikely event of the Speaker resigning immediately before the commencement of the proceedings, a protem speaker would be appointed, who conventionally is the senior most sitting MP in the Lok Sabha.
For any 'no-confidence motion' prior notice is required. Since, per your query there is no prior notice, such 'No Confidence Motion' won't and can't take priority over the 'Confidence' Motion moved and notified prior thereto.
